Prescribed Performance Trajectory Tracking Control for an Underwater Vehicle-Manipulator System with FPTPPF

The problem of prescribed performance control for an underwater vehicle-manipulator system (UVMS) is investigated. Firstly, we design a predefined time control strategy that enables the system to achieve convergence within a predefined time. Secondly, considering the transportation and grasping work to be performed by the UVMS and to overcome the weaknesses of the existing predetermined performance functions, this project proposes to design an improved flexible predefined time-prescribed performance function (FPTPPF). Then, to ensure that the tracking error has a small overshoot, a control framework of an error transformation function with FPTPPF is employed, which achieves good tracking performance. And a new filter is designed to avoid the “complexity explosion” problem of the backstepping algorithm. Finally, the Lyapunov stability theory is used to prove the predetermined time stability of the closed-loop system, and the effectiveness of the control strategy is verified via numerical simulation.